The present invention relates to an outsole for an article of footwear having protruding members that provide directional stability, and more particularly to an athletic shoe having protruding traction elements that resist slippage caused by movement of the body tending to shift the feet with respect to the ground surface, and still more particularly, the invention relates to golf shoes having cleat members and traction elements, the latter oriented and shaped to resist rotational shear force slippage due to a golf swing moving the body and tending to shift the golfer""s feet with respect to the ground surface.
Golf is one of the oldest international sports having its formal source of origin with royal and ancient golf clubs of St. Andrew, Scotland. Over time, golf has gained a populous following due to its prestigious reputation, its challenges, and its suitability for relaxation.
Proper athletic shoes for golf have evolved over time to meet growing demands. Outsoles for golf shoes are of particular interest especially with respect to enhancing performance in the game by insuring controlled contact with the ground while pivoting the body for purposes of swinging a golf club.
Traditional golf shoe outsoles included spikes for engaging the ground to aid in preventing slippage of each foot during the back swing and follow through swing of a golf club. Six or seven removeable spikes were typically located in the forefoot region of the outsole and two to four removeable spikes were located in the rearfoot region (i.e., heel) of the outsole. The traditional golf shoe outsole generally included a planar and often leather walking surface in which the spikes were fixed or removeably anchored.
From the mere use of spikes, modifications to golf shoe outsoles have been made. For example, U.S. Pat. No. 4,885,851 to Peterson includes an outsole having a flat, ground engaging surface with spikes in the forefoot and rearfoot regions positioned and along an inner and outer sides of the outsole. The outsole of Peterson includes supplementary protrusions distributed along an inner side of the right foot shoe and along an outer side of the left foot shoe (for a right handed golfer having a left foot closest to the flag). One purpose of the supplementary protrusions is to inhibit slippage as the golfer shifts his weight from the right foot to the left foot while swinging a golf club from right to left. A drawback of this design, however, is that right and left handed golfers require different shoe models since left handed golfers shift their body weight to opposite sides of the shoes as compared to right handed golfers.
U.S. Pat. No. 6,161,315 to Dalton illustrates a golf shoe having removeable spikes, and additional mini spikes and ridges, In particular, a ridge is disposed along the perimeter of the forefoot, the heel, or both.
Another golf shoe outsole is shown by the U.S. Pat. No. 6,016,613 to Campbell et al., which includes traction projections extending generally radially outward from a pivot point in the forefoot region and another pivot point in the rearfoot region.
In order to fully appreciate the present invention and its uniqueness, one should understand a golf swing and its complex, coordinated side-to-side and twisting motion that involves the arms, torso, hips, legs, and knee, ankle and foot joints of the golfer. Initially, a golfer""s weight is uniformly distributed over each foot with a majority of gravitational force vertically downward and with very little lateral or medial shear force of the bottom of the feet with respect to the ground surface. As a golfer begins the back swing, the rearfoot farthest from the flag known as the driving foot, tends to experience a greater vertical force and tends to rotate lateral outward at the forefoot region and medially inward at the rearfoot region. During the back swing, this driving foot acts as a bracing foot and serves to counter rotational force of the legs, hips, and upper body of the golfer. At the same time, most of the golfer""s weight shifts to the bracing foot so that the forward foot closest to the flag known as the stabilizing foot, has almost all of the golfer""s weight pulled off of it.
After the club head crests and as the golfer begins the down swing to follow-through, the golfer""s weight is shifted from the rear driving foot to the forward stabilizing foot causing the stabilizing foot to become the new bracing foot. The new bracing foot has a tendency to rotate similar to the first bracing foot, that is, rotate laterally outward at the forefoot region and medially inward at the rearfoot region.
It is desirable to prevent rotation of the foot serving as the bracing foot for stability and to enhance strength and accuracy in performance. It is also desirable to permit the foot acting as the non-bracing foot to release slightly from the ground surface to prevent undue stress and strain on non-bracing foot.
In view of the foregoing, a need exists for an outsole of an athletic shoe that has traction elements that tend to resist rotational movement toward a lateral side of the forefoot and toward a medial side of the rearfoot. In addition, a need exists for an outsole capable of providing release in opposing directions to prevent undue foot and ankle strain of the wearer.
The present invention is directed to an article of footwear having an outsole that has a base surface exposed to a ground surface and a plurality of traction elements extending from the base surface which tend to resist lateral rotation. The traction elements may be in addition to removeable or fixed cleat members.
The traction elements are oriented to prevent clockwise rotation of the right foot and counter-clockwise rotation of the left foot from the perspective of looking down at the tops of the feet. For serving this purpose, the traction elements have resist surfaces connected substantially perpendicular to a base surface of the outsole of a shoe. The resist surfaces are oriented to resist shear force slippage of the outsole in the above identified directions with respect to the ground surface. In order to resist shear forces in the aforementioned directions, the rearfoot region traction elements have resist surfaces facing a medial edge of the rearfoot region so as to resist rotational slippage of the rearfoot region in the medial direction; and the forefoot region traction elements are oriented so that the resist surfaces are generally facing a lateral edge of the forefoot region so as to resist rotational slippage of the forefoot in the lateral direction. Since the lateral edge of a shoe typically curves in the forefoot region, the resist surfaces splay generally radially outward to face the lateral edge. A localized region located medial to the forefoot region may be a source origin for the radially outward splay of traction elements.
The traction elements may each be composed of two plate portions and a spacer portion sandwiched therebetween forming a generally rectangular or parallelogram element, in plan view, that can be integrally formed or made of separate members. The two plate portions of the traction elements can protrude vertically and horizontally farther from the base surface than the sandwiched spacer portions for providing plate portion edges that tend to depress into a ground surface more readily than a flat topped or flat sided traction element. Sides of the plate portions may flare outward in a direction from a tip thereof to a base surface in plan view. The traction elements are connected to the base surface with concave curvatures along three edges to aid in preventing clogging of the outsole with mud and other debris.
Various advantages and features of novelty which characterize the invention are pointed out with particularity in the claims. However, for a better understanding of the invention, its advantages, and objects obtained by its use, reference should be made to the drawings and to the accompanying descriptive matter, in which there is illustrated and described one or more preferred embodiments of the invention.